The present invention relates to a new and distinctive garden bean (Phaseolus vulgaris L.) variety, designated 208996. There are numerous steps in the development of any novel, desirable plant germplasm. Plant breeding begins with the analysis and definition of problems and weaknesses of the current germplasm, the establishment of program goals, and the definition of specific breeding objectives. The next step is selection of germplasm that possesses the traits to meet the program goals. The goal is to combine in a single variety an improved combination of desirable traits from the parental germplasm. These important traits may include fresh pod yield, higher seed yield, resistance to diseases and insects, better stems and roots, tolerance to drought and heat, and better agronomic quality. With mechanical harvesting of many crop, uniformity of plants characteristics such as germination and stand establishment, growth rate, maturity and plant height is important.
Choice of breeding or selection methods depends on the mode of plant reproduction, the heritability of the trait(s) being improved, and the type of cultivar used commercially (e.g., F1 hybrid cultivar, pureline cultivar, etc.). For highly heritable traits, a choice of superior individual plants evaluated at a single location will be effective, whereas for traits with low heritability, selection should be based on mean values obtained from replicated evaluations of families of related plants. Popular selection methods commonly include pedigree selection, modified pedigree selection, mass selection, and recurrent selection.
The complexity of inheritance influences choice of the breeding method. Backcross breeding is used to transfer one or a few favorable genes for a highly heritable trait into a desirable cultivar. This approach has been used extensively for breeding disease-resistant cultivars. Various recurrent selection techniques are used to improve quantitatively inherited traits controlled by numerous genes. The use of recurrent selection in self-pollinating crops depends on the ease of pollination, the frequency of successful hybrids from each pollination, and the number of hybrid offspring from each successful cross.
Each breeding program should include a periodic, objective evaluation of the efficiency of the breeding procedure. Evaluation criteria vary depending on the goal and objectives, but should include gain from selection per year based on comparisons to an appropriate standard, overall value of the advanced breeding lines, and number of successful cultivars produced per unit of input (e.g., per year, per dollar expended, etc.).
Promising advanced breeding lines are thoroughly tested and compared to appropriate standards in environments representative of the commercial target area(s) for three or more years. The best lines are candidates for new commercial cultivars; those elite in traits are used as parents to produce new populations for further selection.
These processes, which lead to the final step of marketing and distribution, usually take from eight to 12 years from the time the first cross is made. Therefore, development of new cultivars is a time-consuming process that requires precise forward planning, efficient use of resources, and a minimum of changes in direction.
A most difficult task is the identification of individuals that are genetically superior, because for most traits the true genotypic value is masked by other confounding plant traits or environmental factors. One method of identifying a superior plant is to observe its performance relative to other experimental plants and to a widely grown standard cultivar. If a single observation is inconclusive, replicated observations provide a better estimate of its genetic worth.
The goal of plant breeding is to develop new, unique and superior garden bean cultivars. The breeder initially selects and crosses two or more parental lines, followed by repeated selfing and selection, producing many new genetic combinations. The breeder can theoretically generate billions of different genetic combinations via crossing, selfing and mutations. The breeder has no direct control at the cellular level. Therefore, two breeders will never develop the same line with the same garden bean traits.
Each year, the plant breeder selects the germplasm to advance to the next generation. This germplasm is grown under unique and different geographical, climatic and soil conditions, and further selections are then made, during and at the end of the growing season. The cultivars which are developed are unpredictable. This unpredictability is because the breeder""s selection occurs in unique environments, with no control at the DNA level (using conventional breeding procedures), and with millions of different possible genetic combinations being generated. A breeder of ordinary skill in the art cannot predict the final resulting lines he develops, except possibly in a very gross and general fashion. The same breeder cannot produce the same cultivar twice by using the exact same original parents and the same selection techniques. This unpredictability results in the expenditure of large amounts of research monies to develop superior new garden bean cultivars.
The development of new garden bean cultivars requires the development and selection of garden bean varieties, the crossing of these varieties and selection of superior hybrid crosses. The hybrid seed is produced by manual crosses between selected parents. These hybrids are selected for certain genetic traits such as pod straightness, erect habit, root structure and disease resistance.
Pedigree breeding and recurrent selection breeding methods are used to develop cultivars from breeding populations. Breeding programs combine desirable traits from two or more cultivars or various broad-based sources into breeding pools from which cultivars are developed by selfing and selection of desired phenotypes. The new cultivars are evaluated to determine which have commercial potential.
Pedigree breeding is used commonly for the improvement of self-pollinating crops. Two parents which possess favorable, complementary traits are crossed to produce an F1. An F2 population is produced by selfing one or several F1""s. Selection of the best individuals may begin in the F2 population; then, beginning in the F3, the best individuals in the best families are selected. Replicated testing of families can begin in the F4 generation to improve the effectiveness of selection for traits with low heritability. At an advanced stage of inbreeding (i.e., F6 and F7), the best lines or mixtures of phenotypically similar lines are tested for potential release as new cultivars.
Mass and recurrent selections can be used to improve populations of either self- or cross-pollinating crops. A genetically variable population of heterozygous individuals is either identified or created by intercrossing several different parents. The best plants are selected based on individual superiority, outstanding progeny, or excellent combining ability. The selected plants are intercrossed to produce a new population in which further cycles of selection are continued.
Backcross breeding has been used to transfer genes for a simply inherited, highly heritable trait into a desirable homozygous cultivar or inbred line which is the recurrent parent. The source of the trait to be transferred is called the donor parent. The resulting plant is expected to have the attributes of the recurrent parent (e.g., cultivar) and the desirable trait transferred from the donor parent. After the initial cross, individuals possessing the phenotype of the donor parent are selected and repeatedly crossed (backcrossed) to the recurrent parent. The resulting plant is expected to have the attributes of the recurrent parent (e.g., cultivar) and the desirable trait transferred from the donor parent.
The single-seed descent procedure in the strict sense refers to planting a segregating population, harvesting a sample of one seed per plant, and using the one-seed sample to plant the next generation. When the population has been advanced from the F2 to the desired level of inbreeding, the plants from which lines are derived will each trace to different F2 individuals. The number of plants in a population declines each generation due to failure of some seeds to germinate or some plants to produce at least one seed. As a result, not all of the F2 plants originally sampled in the population will be represented by a progeny when generation advance is completed.
Descriptions of other breeding methods that are commonly used for different traits and crops can be found in one of several reference books (e.g., Allard, 1960; Simmonds, 1979; Sneep et al., 1979; Fehr, 1987).
Proper testing should detect any major faults and establish the level of superiority or improvement over current cultivars. In addition to showing superior performance, there must be a demand for a new cultivar that is compatible with industry standards or which creates a new market. The introduction of a new cultivar will incur additional costs to the seed producer, the grower, processor and consumer; for special advertising and marketing, altered seed and commercial production practices, and new product utilization. The testing preceding release of a new cultivar should take into consideration research and development costs as well as technical superiority of the final cultivar. For seed-propagated cultivars, it must be feasible to produce seed easily and economically.
Garden bean, Phaseolus vulgaris L., is an important and valuable vegetable crop. Thus, a continuing goal of plant breeders is to develop stable, high yielding garden bean cultivars that are agronomically sound. The reasons for this goal are obviously to maximize the amount of yield produced on the land. To accomplish this goal, the garden bean breeder must select and develop garden bean plants that have the traits that result in superior cultivars.
According to the invention, there is provided a novel garden bean cultivar, designated 208996. This invention thus relates to the seeds of garden bean cultivar 208996, to the plants of garden bean 208996 and to methods for producing a garden bean plant produced by crossing the garden bean 208996 with itself or another garden bean line.
Thus, any such methods using the garden bean variety 208996 are part of this invention: selfing, backcrosses, hybrid production, crosses to populations, and the like. All plants produced using garden bean variety 208996 as a parent are within the scope of this invention. Advantageously, the garden bean variety could be used in crosses with other, different, garden bean plants to produce first generation (F1) garden bean hybrid seeds and plants with superior characteristics.
Parts of the garden bean of the present invention such as ovule and pollen are also provided.
In another aspect, the present invention provides regenerable cells for use in tissue culture of garden bean plant 208996. The tissue culture will preferably be capable of regenerating plants having the physiological and morphological characteristics of the foregoing garden bean plant, and of regenerating plants having substantially the same genotype as the foregoing garden bean plant. Preferably, the regenerable cells in such tissue cultures will be embryos, protoplasts, seeds, callus, pollen, leaves, anthers, roots, and meristematic cells. Still further, the present invention provides garden bean plants regenerated from the tissue cultures of the invention.
In another aspect, the present invention provides for single gene converted plants of 208996. The single transferred gene may preferably be a dominant or recessive allele. Preferably, the single transferred gene will confer such trait as herbicide resistance, insect resistance, resistance for bacterial, fungal, or viral disease, enhanced nutritional quality, and industrial usage. The single gene may be a naturally occurring bean gene or a transgene introduced through genetic engineering techniques.
The invention further provides methods for developing bean plants in a bean plant breeding program using plant breeding technique including recurrent selection, backcrossing, pedigree breeding, restriction fragment length polymorphism enhanced selection, genetic marker enhanced selection and transformation. Seeds, bean plant, and parts thereof produced by such breeding methods are also part of the invention.
In the description and tables which follow, a number of terms are used. In order to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms, the following definitions are provided:
Maturity Date. Plants are considered mature when the pods have reached their maximum allowable seed size and sieve size for the specific use intended. This can vary for each end user, e.g., processing at different stages of maturity would be required for different types of consumer beans such as xe2x80x9cwhole pack,xe2x80x9d xe2x80x9ccutxe2x80x9d or xe2x80x9cfrench stylexe2x80x9d. The number of days are calculated from a relative planting date which depends on day length, heat units and environmental other factors.
Sieve Size (sv). Sieve size 1 means pods which fall through a sieve grader which culls out pod diameters of 4.76 cm through 5.76 cm. Sieve size 2 means pods which fall through a sieve grader which culls out pod diameters of 5.76 cm through 7.34 cm. Sieve size 3 means pods which fall through a sieve grader which culls out pod diameters of 7.34 cm through 8.34 cm. Sieve size 4 means pods which fall through a sieve grader which culls out pod diameters of 8.34 cm through 9.53 cm. Sieve size 5 means pods which fall through a sieve grader which culls out pod diameters of 9.53 cm through 10.72 cm. Sieve size 6 means pods which fall through a sieve grader which culls out pod diameters of 10.72 cm or larger.
Bean Yield (Tons/Acre). The yield in tons/acre is the actual yield of the bean pods at harvest.
Plant Height. Plant height is taken from the top of soil to top node of the plant and is measured in centimeters.
Allele. Allele is any of one or more alternative forms of a gene, all of which alleles relate to one trait or characteristic. In a diploid cell or organism, the two alleles of a given gene occupy corresponding loci on a pair of homologous chromosomes.
Backcrossing. Backcrossing is a process in which a breeder repeatedly crosses hybrid progeny back to one of the parents, for example, a first generation hybrid F1 with one of the parental genotypes of the F1 hybrid.
Quantitative Trait Loci (QTL). Quantitative trait loci (QTL) refer to genetic loci that control to some degree numerically representable traits that are usually continuously distributed.
Regeneration. Regeneration refers to the development of a plant from tissue culture.